In the Family Way by Cate House

ate one night Stan Beyler arrived at the airport after a business trip and boarded a shuttle to his car. It wasn’t crowded, so Beyler noticed that a muscular man dressed in leather and seated at the back of the bus was staring at him. This made Beyler a bit uneasy. Suddenly the man in leather blurted out, “Hey! You’re the man who got my wife pregnant.” Anticipating trouble, the other passengers braced themselves against their seats, but Beyler calmly replied, “Oh sure, I remember you. How are you doing?”

As it happens Beyler had only been doing his job. He’s a scientist who works with fertility specialists to help couples conceive.

Despite the vast number of unintended pregnancies each year in the United States—about 3 million according to the Alan Guttmacher Institute—getting pregnant can sometimes be extraordinarily difficult. Up to 10 million American couples are infertile, and many spend years trying to conceive, often without success. In vitro fertilization (IVF)—commonly known as “test tube” pregnancy—has helped many couples achieve their dream of having a child. Since 1978, there have been more than 300,000 successful IVFs worldwide. At Carolina around 125 couples undergo IVF each year. About 40 percent become pregnant and around 30 percent end up with a live birth.

While that rate may seem low, Beyler, clinical assistant professor of obstetrics and gynecology and director of the clinical andrology and embryology laboratory, explains this rate is actually similar to “natural” conception rates. Even with no fertility problems and no contraceptive use, only one in three reproductive cycles will result in successful pregnancy.

Beyler also explains that IVF is only successful when both parties have functioning gametes—eggs or sperm. If a woman’s egg quality is poor, then an egg donor is a possible alternative. Older women, for example, may still be able to carry a child, but their eggs might be “worn out.” A woman is born with all the eggs she will ever have—about 2 million—but by the time she reaches puberty there may be only about 400,000 left. By the time she gets to be about 40, there may be very few good quality eggs left.

f a man isn’t able to produce sperm, then the only option is to use donor sperm. But even if a man has a low count, Beyler says pregnancy is possible. Sometimes the sperm just needs a little help reaching its destination. Even when a man has a normal sperm count, less than 1 percent of the sperm present in the ejaculate actually make it into the woman’s uterus, and fewer still make it to the actual site of fertilization—the fallopian tube. In this case, Beyler can use a procedure—interuterine insemination—in which the man’s sperm is taken directly from his testicles and injected into the woman’s uterus when she’s ovulating. But that doesn’t guarantee fertilization.

M. G. O’Rand, professor of cell biology and anatomy and one of the founders of UNC’s IVF program, studies sperm-egg interaction. To understand the process, consider the design of a human egg. Each egg has a shell around it, called a zona pellucida, that protects the egg, provides a secure place for the embryo to grow, and keeps extra sperm from getting in. First, the sperm has to penetrate the shell, and then it has to fuse with the egg.

In each of these steps, certain proteins in the sperm are involved. “If a man is infertile, one or more of those proteins may be missing or nonfunctional,” O’Rand says. “We’re trying to understand the basic biology of each of those steps—figure out which proteins are needed for which step.”

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